Metallic tube furnace



April 3, 1951 A. J. PERLE METALLIC TUBE FURNACE Filed Ool.. 4, 1946 lll/l far/75m:

Patented pr. 3, 1,*951

METALLIC TUBE FURNACE Abe J. Perle, Orange, N. J., assigner tovPersiro Manufacturing Corp., Newark, N. J., a corpo ration of'New Jersey Application October 4, 1946, Serial No. 701,153

1 Claim.

This invention relates to water and steam heating plants, and more particularly to a combined boiler and burner unit adapted for use in homes. The-invention consists of a metallic combustion tube and a flue tube extending along the length thereof, forming an annular space between the tubes, said fiue tube having its receiving end abutting the periphery of a iiow reverser to receive in said annular space the products of combustion from the iiow reverser and guide them along the exterior of the combustion tube and over any incandescent part thereof, and a spinner disposed between the discharge end of the combustion tube and the receiving end of the flue tube to spiral the products of combustion directed by the flow reverser into the annular space between the tubes, for preventing the combustion tube from reaching a harmful high temperature.

The invention will be further described, an ernbodiment shown in the drawings, and the invention will be finally pointed out in the claim.

In the accompanying drawings, in which like reference characters indicate corresponding parts throughout the various Views:

Figure l is an end elevation View of the boiler arrangement, showing the burner and air head connected thereto and the blower for supplying air to the head.

Figure 2 is a longitudinal cross-sectional View taken through the combined boiler and burner unit, showing the burner head in section, but showing in side elevation the motor and the air andfuel pumps; and Figure 3 is an enlarged fragmentary front elevational View of the spinner, and

Figure 4 is a view taken on the line II-- of Figure 3 and looking in the direction of the arrows, the view illustrating the angular arrangement of the spinner blades.

Referring now to the figures, I represents a boiler shell or casing having an inlet II at its bottom and an outlet I2 at its top. The ends of the boiler casing are closed by heads I3 and I4. On the head I3 is a casting i5 adapted to receive water through an opening I6 at the bottom of the head and direct same upwardly to an opening I6 at the top of the head. This casting- I4 has an opening I'I therein adapted to support a combustion tube i8. The combustion tube is formed of a high chrome, type 446 stainless steel which is resistant to oxidation up to a temperature of 2150 degrees Fahrenheit.

The combustion tube I8 extends into the boiler and is surrounded by a circular fire tube or boiler iiue I9 having its walls rigidly spaced from the combustion tube so as to forma surrounding annular chamber. This ue I9 is connected at its ends to the head members I3 and I4 and has ns 2l for projecting the heat into the water mass ofthe boiler III. Above the flue or re tubel I9 2 y are three spaced flue or nre tubes 22, each having heat projecting iins 23 on the outer periphery surface thereof.

The gases which are projected through the combustionl tube IS, by means to be presently described, pass to the rear end of the boiler and are thrust against a refractory deflecting means or bafiie 2t. This deflecting member or baffle 24 is held on the head Il? by a casing 25 having a main chimney 26 therein. The refractory return bale 2i', is brought to a high incandescent heat so that any unburned fuel gases which may Strike it are oxidized before the gases are caused to fiow counter-current through the annular cham- Between the end of the combustion tube adjacent the bafile 2f. and the flue IS there is pro-l vided a spinner 2l' which imparts a tangential component to the gas flow to make up for any whirl which may have been lost by impingement on the baille 2t and the reversal of the gas flow after leaving the end of the combustion tube I8. The spinner 2l is rigidly connected to the inside of flue IQ but suiiciently large on its inside diameter to allow the free sliding of combustion tube I8' through its center. The combustion tube I8 is thus supported at both ends but free to expand and contract as required. The spinner 2 embodies an annular collar having a plurality of spaced angularly disposed blades 2' projecting from a face thereof, the angular disposition of said blades being such as to induce rotative peripheral movements to the products of combustion flow.

The products of combustion or gases now in a counter-current direction through the annular chamber and impart heat to the wall thereof which heat is in turn transferred by convection to the Water body of the boiler. The gases are then collected in a chamber 28 within the casting I5 and are directed upwardly to the flue tubes 22, each of which contains a spirally shaped element or spinner 29, which imparts a spiral travel to the gases insuring the complete washing of the inside of the tube walls and maximum heat transfer to the boiler water. On leaving the fire tubes 22, the gases will then go to the chimney 26 for dissipation to the atmosphere.

On the structure I5 and communicating with the fire tube I8 is a combustion head 3i comprising an air inlet portion 32 and an oil inlet structure 33, supporting a spray nozzle.

A slow burning iiame is started and this mass is whirled through the combustion tube, being thrown circumferentially and tangentiaily against the combustion tube by centrifugal force, heating this tube to a red heat. Once the combustion tube reaches this elevated temperature, it acts as a pilot to ignite any oil particles which may not have been touched off by the'initial ignition of the fuel particles at the combustion head. The red hot Walls of the combustion tube also act as a converter to materially assist in the further oxidation of the carbon monoxide formed in the initial stages of the combustion and converts the monoxide to carbon dioxide. This secondary burning of carbon monoxide increases the overall efliciency of combustion by releasing more of the energy stored in the fuel. The burning gases, because of the rotary cornponents imparted by passage through the spinner 21, are thrown centrifugally against the primary heating surface of the boiler flue i9. This insures a high rate of heat transfer through the broiler flue I9 into the Water mass of the boiler. As .the hot products of combustion spiral through the annular chamber betvveen combustion tube I8 and boiler flue I9 they become cooled due to heat transfer through the boiler flue to the surrounding Water. The gases thus cool the outside of the combustion tube i8 and prevent said tube from reaching an excessively high temperature at which the stainless steel might be melted or oxidized. IIn addition, the combustion tube I8 is cooled by the transfer of radiant heat to boiler flue I9 as previously explained, as Well as by conduction through contact with the boiler head casting I and spinner 2'I at either end. The combustion tube operates at a temperature of 1700` to 1850 degrees Fahrenheit which is high enough to catalyze the oxidation of carbon monoxide to carbon dioxide, but at the same time low enough to prevent oxidation or melting of the combustion tube I8. The fins 2l and 23 afford an extremely large surface to complete the transfer of heat from the tubes to the boiler Water. The tubes are so placed that the extended heating surface sections completely cover the crosssection of the boiler. The multitude of iins provides a very large total heating surface so disposed as to "comb the entire cross-section of the boiler and break up any steam pockets rising from the outside surfaces of either boiler flue I9 or fire tubes 22. This feature eliminates priming or the entrainment of Water with the steam delivered from the boiler Which is an evil usually inherent to the design of small or rapid steaming boilers.

Additional heatingsurface, as indicated at 65, is gained Where the gases contact the back Wall of casing I4. While detailed changes may be made in the construction of the various parts and in the arrangement of same, it shall be within the spirit and scope of the present invention as defined in the appended claim. Although the drawings shown indicate the use of oil or other liquid fuel, it is to be understood that the invention is suitable for the combustion of gaseous or liquied hydrocarbon fuels by substitution of a nozzle suitable to fuel being burned.

The invention provides a boiler burner unit which will have a high chrome stainless steel combustion tube so designed and arranged as to give the following advantages. First, the design of the combustion tube and its placement in the boiler in conjunction with the special fuel and air handling parts in the combustion head, allows the complete and efficient combustion of the fuel in a fraction of the furnace volume heretofore found impossible in commercial practice for domestic heating plants. Secondly, the design and placement of the combustion tube is such that the tube very rapidly reaches an operating temperature in the incandescent range and is held at this temperature by a counter-current fiow of cooling gases around its periphery. Be-

cause this combustion tube is in close proximity to a Water backed heating surface it is able to effect a transfer of its radiant heat tothe cooler surface. Since the rate of radiant heat transfer varies directly as the fourth power of the absolute temperature, it can readily be seen that if a slight increase in operating temperature above the normal should be encountered in the metal surface of the combustion tube, the immediate increase of radiant heat transfer to the surrounding furnace flue would cool the combustion tube back to the normal again. This self-regulatory feature of the design makes possible the use of a thin wall metallic combustion tube instead of present day heavy fragile refractories.

This invention provides a boiler-burner unit which is so designed as to employ a minimum of refractory material. The entire combustion tube and refractory may be factory assembled as integral parts of a packaged unit. This eliminates installation Work by the consumer of refractories and assures a better as Well as a more economical job.

The invention provides a boiler-burner unit Which will operate at a high positive overre presure, i. e. above atmospheric. This assures more rapid and complete combustion of the fuel. The boiler is so designed that despite the positive overre pressure none of the products of combustion may escape from the boiler from any opening other than the chimney during the operation of the boiler. f

The invention provides a boiler-burner unit Which is made of Welded steel plate, all heat transfel` surfaces being of stainless steel to .prevent corrosion which would gradually decrease the rate of heat transfer. The assembly includes a boiler iiue to separate the heating flame from the Water and which is adapted to contain a central combustion tube through Which the fiames are projected onto a deflecting means of high temperature retaining molded refractory material. The deflecting means serves to reverse the flow of the burning gases and products of combustion, and, due to the refractory nature of the material, it reaches an incandescent condition. Any carbon monoxide, as yet unburned, upon becoming intimately contacted With the incandescent surface is immediately converted to carbon dioxide. The heated products of combustion are then caused to flow counter-current through an annular chamber surrounding the combustion tube and thence upwardly vand through a plurality of spaced flue tubes `arranged above the annular chamber and extending horizontally through the boiler shell, the dow of the products of combustion being in reverse direction to that of the annular chamber flow. The products of combustion upon egress from the flue tubes are discharged through a chimney provided in the boiler shell.

The burner is the subject matter of a cepending divisional application filed on March 28, 1947, under Serial Number 737,862 and no claim to the burner is made herein.

wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications Will occur to a @arson skilled in the art.

I claim:

In a metallic tube furnace, the'combination With a metallic cylindrical combustion tube of stainless steel of high chrome type 446, adapted to temperatures of 2l50 F., having one end to receive burning fuel and air. and having its other end open to discharge the products resulting from the combustion thereof, a 110W reverser of refractory material spaced from the discharge end-of the combustion tube, and in the path or the discharging products of combustion, to reverse the flow of said products, a metallic cylindrical ue tube ccncentri-ca-lly spaced :from the exterior of the combustion tube and extending along the length thereof, forming an annular space between the tubes, and having its receiving end abutting the periphery of the ow reverser to receive in said annular space the products of combustion from the flow reverser and guide them along the exterior of the combustion tube and over any incandescent part thereof, of a spinner disposed between the discharge end of the combustion tube and the receiving end of the ue tube to spiral the products of combustion directed by the flow reverser into the annular space between the tubes, for preventing the combustion tube from reaching a harmful high temperature.

ABE J. PERLE.

e REFERENCES CITED The following references are of record i th le of this patent:

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